JP2012509627A - Optical switching method and apparatus - Google Patents

Abstract

  An optical switching method and apparatus are provided. The method receives an input light wave, and if the input light wave needs to be grouped, it switches the input light wave to an optical grouping unit, then receives the grouped light wave, and outputs the grouped light wave For switching to a corresponding output port. The apparatus includes an optical switching unit and an optical grouping unit, and part of the output port of the optical switch unit is connected to the input port of the optical grouping unit, and the output port of the optical grouping unit is connected to the input port of the optical switching unit. Connected, the optical switching unit is used to control the transmission path of the light wave, and the optical grouping unit is used to group the light wave.

Description

This application claims the priority of Chinese Patent Application No. 200810177646.1 filed on November 20, 2008, entitled “METHOD AND DEVICE FOR OPTICAL SWITCHING”. Which application is incorporated herein by reference in its entirety.
The present invention relates to the field of communication technology, and in particular, to an optical switching method and apparatus.

  Current Dense Wavelength Division Multiplexing (DWDM) technology allows a single optical fiber to accommodate hundreds of wavelengths, with each wavelength reaching 40 Gbit / s or even 100 Gbit / s With speed, the capacity of one optical fiber reaches the size of T bits / s and meets the demand for network bandwidth. At the same time, DWDM technology significantly increases network costs and control complexity. As the number of wavelengths accommodated in an optical fiber reaches hundreds, the number of ports for optical fiber switching and wavelength switching within the optical cross-connect (OXC) increases significantly, and the cost of optical switching Will increase significantly. At the same time, the larger the scale of OXC, the more difficult and complex it becomes to control OXC. Assuming that 20 input optical fibers and 20 output optical fibers are provided at the node, and 100 wavelengths are transmitted simultaneously within each optical fiber, 2000 when a common OXC node is used. Input ports, 2000 output ports, and a 2000 × 2000 optical switch matrix are required, resulting in the high cost and complexity of OXC. Furthermore, the development of networks towards dynamic full mesh networks has higher demands on the service signal dimension. The dynamic and flexible nature of the network imposes higher demands on the service signal dimensions because the wavelengths are dispatched over time and at different times the dimensions of the wavelengths that need to be switched are different. . Therefore, switching configurations that can achieve multiple granularities and multiple dimensions, are scalable, and can be flexibly upgraded are very useful for building and managing dynamic networks. is important.

  In order to solve the problems of increased switching costs and control complexity brought about by the development of optical network technology, multi-grain optical switching technology has been defined. Multi-grain optical switching technology means that optical fiber switching, wavelength band switching, and wavelength switching are performed simultaneously in the same optical node. Waveband switching refers to the fact that multiple wavelengths form a wavelength band for performing switching together, reducing the number of ports required for switching and reducing costs. At the same time, three switching granularities are provided: optical fiber, wavelength band, and wavelength, which can be flexibly adjusted according to service requirements, thus reducing control complexity.

  Multi-grain optical switching technology can be realized by an optical switching configuration using multiplexer and demultiplexer (DEMUX) loopback. This solution allows the added / dropped wavebands and wavelengths to be dynamically switched and transmitted transparently. Each output port of the DEMUX loopback has a cycle passband, so any wavelength band can be demultiplexed to a single wavelength. The DEMUX splits the input DWDM channel into wavelength bands and transmits the wavelength bands directly to the optical switch, which then dispatches the wavelengths on demand. This solution can achieve switching at the optical fiber level, wavelength level, and wavelength band level.

  In practice, however, not all wavelengths need to be demultiplexed to a single wavelength by DEMUX for switching. According to the above solution, DEMUX demultiplexes all wavelengths into a single wavelength wave and transmits the wave to the switching unit, thus occupying the switching port and wasting the port of the optical switching unit. The

  Accordingly, the present invention relates to an optical switching method and apparatus for saving switching ports.

To achieve the above object, an optical switching method according to an embodiment of the present invention includes:
Receive the input optical signal,
When the input optical signal needs to be grouped, switch the optical signal to the optical grouping unit, receive the grouped optical signal,
Switching the grouped optical signals to corresponding output ports for output;
Realized by technical solutions including:

One embodiment of the present invention receives an optical signal switched by an optical switching device,
Group optical signals,
Transmitting the grouped optical signals to an optical switching device;
And further providing another optical switching method.

  One embodiment of the present invention further provides an optical switching device including an optical switching unit and an optical grouping unit.

  A part of the output port of the optical switching unit is connected to the input port of the optical grouping unit, and the output port of the optical grouping unit is connected to the input port of the optical switching unit.

  The optical switching unit is configured to control the transmission path of the optical signal, and the optical grouping unit is configured to group the optical signal.

  This technical solution uses an optical grouping unit to group optical signals and then uses an optical switching unit to switch the optical signals so that the optical signals are combined on demand. This has the beneficial effect of reducing the requirements for the switch matrix and saving the ports of the optical switching unit.

It is a schematic block diagram of the apparatus by the 1st Embodiment of this invention. It is a schematic block diagram of the optical switching unit by the 1st Embodiment of this invention. It is a schematic block diagram of the optical switching unit by the 1st Embodiment of this invention. It is a schematic block diagram of the optical grouping unit by the 1st Embodiment of this invention. It is a schematic block diagram of the apparatus by the 2nd Embodiment of this invention. It is a schematic block diagram of another apparatus by the 2nd Embodiment of this invention. It is a schematic block diagram of another apparatus by the 2nd Embodiment of this invention. It is a schematic block diagram of the apparatus by the 3rd Embodiment of this invention. It is a schematic block diagram of another apparatus by the 3rd Embodiment of this invention. It is a schematic block diagram of the apparatus by the 4th Embodiment of this invention.

  The present invention provides an optical switching method and apparatus for saving switching ports.

In one embodiment, the present invention provides:
When an input optical signal is received and the input optical signal needs to be grouped, the input optical signal is switched to the optical grouping unit, the grouped optical signal is received, and the grouped optical signal is output for output. Switching to the corresponding output port,
An optical switching method is provided.

  When the optical signal switched by the optical switching unit after receiving the input optical signal requires service switching, the method transmits the input optical signal to the service switching unit and receives the service-switched optical signal. And switching the service-switched optical signal to a corresponding output port for output.

  Outputting the grouped optical signal on the corresponding output port switches part of the grouped optical signal to the optical grouping unit, receives the regrouped optical signal, and other parts of the optical signal May be switched to a corresponding output port for output, and the regrouped optical signal may be switched to a corresponding output port for output.

  The implementation of the above solution may be a strictly non-blocking optical switch.

From another point of view, this switching method
Receiving optical signals switched by the optical switching device, grouping the optical signals, and transmitting the grouped optical signals to the optical switching device;
May be included.

  The optical signals switched by the optical switching device include grouped optical signals.

  The implementation target of this solution may be a wavelength selective switch (WSS).

  The method according to the previous embodiment will be further described with reference to the apparatus according to the subsequent embodiment.

  The optical switching process is completed by grouping optical signals using an optical grouping unit and then switching the optical signals using an optical switching unit. Since the optical signals are combined on demand, the demand on the switch matrix is reduced and the ports of the optical switching unit are saved.

<First Embodiment>
As shown in FIG. 1, the optical switching device according to this embodiment of the present invention includes an optical switching unit 102, an optical grouping unit 103, and a service switching unit 101. This embodiment of the invention will be described in the context of multi-granular switching.

  The optical switching unit 102 has an optical input port and an optical output port, and a part of the optical output port is connected to the input port of the optical grouping unit 103.

  The optical grouping unit 103 has an optical input port and an optical output port. The optical input port of the optical grouping unit 103 is connected to the optical output port of the optical switching unit 102, and the optical output port of the optical grouping unit 103 is , Connected to the optical input port of the optical switching unit 102.

  The optical switching unit 102 is configured to control the transmission path of the optical signal. For example, as shown in FIGS. 2A and 2B, the optical switching unit 102a has an input and output function on a random port, and the optical switching unit 102b receives inputs from a plurality of ports. It has the function to output to. The optical grouping unit 103 is configured to group optical signals. For example, as illustrated in FIG. 2C, the optical grouping unit 103a has a function of randomly grouping and outputting input optical fiber wavelengths. It will be understood that the function of receiving input from multiple ports and outputting on one port in FIG. 2B may be realized by the optical grouping unit 103a. As a specific example, when optical signals are grouped, optical signals are received from a plurality of ports and output from the same output port (the optical signal path is shown in FIG. 2C). In the opposite direction to the path shown). 2A and 2B, a line without an arrow represents an input port or an output port, while a line with an arrow represents an optical transmission path (trace).

  In the following, this embodiment of the present invention will be described using several general implementations of granularity switching.

Optical fiber switching: As shown by the path of optical fiber B in FIG. 1, the input optical fiber can be output directly from any port via the optical switching unit 102.

The flow of optical fiber switching is as follows.
Input optical fiber B → optical switching unit 102 → output optical fiber B

Wavelength grouping and wavelength switching: The wavelengths in the input optical fiber can be randomly grouped via the optical grouping unit 103, and as shown in FIG. C2 are grouped and output from ports O3 and O4, respectively, that is, output from output optical fiber C1 and output optical fiber C2, respectively.

The flow of wavelength grouping and wavelength switching is as follows.

Sub-wavelength switching: after service switching is performed by electrical cross-connect (EXC) for wavelengths in the input optical fiber, the wavelengths are loaded into other random optical fibers. As shown in FIG. 1, the wavelength in the input optical fiber A passes through a service switching unit 101, which may be formed from wavelength division multiplexing (WDM) -EXC-WDM, WDM-EXC -After service switching by WDM, the wavelength in input optical fiber A can be output from O1, but it is clear that the wavelength may be loaded into other groups for output.

The flow of sub-wavelength switching is as follows.

  From this solution, it can be seen that the present apparatus may include only the optical grouping unit 103 and the optical switching unit 102.

  The optical switching unit 102 may be a strictly non-blocking optical switch and may have a single level configuration or a cascade configuration, for example, a single level configuration of a three-dimensional microelectromechanical system (3D MEMS). Also good. The optical grouping unit 103 can realize any wavelength combination, and may include one or more WSSs, and the number of WSSs is the maximum of the switching dimension of the network node configured by the optical switching configuration in the network. The size of the optical switching unit 102 may be the sum of the number of input optical fibers at the peak and the number of switching dimensions. This embodiment of the present invention does not limit the specific forms of the optical switching unit 102 and the optical grouping unit 103, and these specific forms do not affect the implementation of the present embodiment.

  Fiber optic switching may be performed directly by the optical switching unit 102, since wavelength grouping and wavelength switching are performed after grouping using the optical grouping unit 103, and the wavelengths are combined on demand, so The demand for the switch matrix is reduced. Nine input optical fibers (F1, F2,..., F9) are provided, the input optical fibers F1 need to be grouped into eight groups at time T1, and F2 is grouped into five groups at time T1. Assume that F3 to F9 need to be directly connected in sequence. Since F1 needs to be grouped into five groups at time T2, and F2 needs to be grouped into eight groups at time T2, the grouping resources occupied by the optical fiber F1 are shared by the optical fiber for sharing. Can be released to F2. If 9 optical fibers need to be grouped into a total of 40 groups at peak time, only 49 × 49 switching units are needed. However, in the industry solution, F1-F9 are connected to the optical switching matrix after DEMUX and have, for example, 80 waves per optical fiber, so the required switching unit size is 720 × 720. It can be seen that the solution of the present invention can significantly reduce the scale requirements for the optical switching unit 102.

  Due to the flexibility of the internal connections in the optical switch, the output of the WSS can be sent to the next level of WSS, realizing a flexible combination of WSS and implementing various dimensions of switching.

<Embodiment 2>
One embodiment of the present invention further provides an optical switching device. This embodiment of the invention will be described in the context of sharing optical grouping units.

  As shown in FIG. 3A, the apparatus can include an optical switching unit 302 and an optical grouping unit 303. The dimension extension is realized by sharing the optical grouping subunit. Assume that at time T1, optical fiber A is required to be output in 9 dimensions and optical fiber B is required to be output in 17 dimensions. As shown in FIG. 3B, at time T2, the optical fiber A is required to be output in 17 dimensions, and the optical fiber B is required to be output in 9 dimensions. As shown in FIG. 3C, at time T3, the optical fiber A is required to be output in seven dimensions, the optical fiber B is required to be output in six dimensions, and the optical fiber A7 and the optical fiber B6 are Need to be combined in one dimension.

  In this embodiment, the optical switching unit may be formed from a 3D MEMS large scale optical switch, and the optical grouping unit may include an optical grouping subunit. It is assumed that the optical grouping subunit has a function of 1-port input and 9-dimensional output. It will be appreciated that the number of input ports and the number of output ports may be other values and these values are not considered a limitation on the present invention.

  At time T1, the input optical fiber A is input to the optical grouping subunit 3 in the optical grouping unit via the optical switching unit to form a nine-dimensional output. Similarly, the optical fiber B is an optical grouping subunit. Through 1 and 2, a 17-dimensional output is formed.

The connection relationship at time T1 is as follows.

  At time T2, the number of output dimensions of the input optical fiber A changes to 17, and the number of output dimensions of the input optical fiber B changes to 9. This change may be implemented by switching the connection between the optical switching unit and the optical grouping subunit between the input optical fibers A and B.

The connection relationship at time T2 is as follows.

At time T3, the number of output dimensions of the input optical fiber A changes to 7, the number of output dimensions of the input optical fiber B changes to 6, and A7 and B6 are combined in one dimension. The total output dimension of optical fibers A and B is 12.

  Furthermore, if the number of output dimensions changes, the optical grouping unit may release the idle optical grouping unit, and the objective of saving the optical grouping subunit is achieved.

  The optical grouping subunit transmits optical signals that need to be regrouped directly to other optical grouping subunits, but this may be implemented in the following manner. The optical grouping unit is formed of an optical grouping subunit that includes a first optical grouping subunit, a second optical grouping subunit, and a third optical grouping subunit.

  The input port of the first optical grouping subunit is connected to the output port of the optical switching unit, and a part of the output port of the first optical grouping subunit is connected to the input port of the third optical grouping subunit. A part of the output port of the first optical grouping subunit is connected to the input port of the optical switching unit.

  An input port of the third optical grouping subunit is connected to an output port of the first optical grouping subunit, and a part of the output port of the third optical grouping subunit is an input of the second optical grouping subunit. A part of the output port of the third optical grouping subunit is connected to the input port of the optical switching unit.

  The input port of the second optical grouping subunit is connected to the output port of the third optical grouping subunit, and the output port of the second optical grouping subunit is connected to the input port of the optical switching unit.

  In this embodiment, the optical switching process is completed by grouping optical signals using an optical grouping unit and then switching the optical signals using an optical switching unit. Since the optical signals are combined on demand, the demand on the switch matrix is reduced and the ports of the optical switching unit are saved. Furthermore, sharing of optical grouping subunits saves optical grouping subunits.

<Embodiment 3>
One embodiment of the present invention provides an optical switching device. This embodiment of the invention is described in the context of dimensional expansion.

  As shown in FIG. 4A, this apparatus includes an optical switching unit 402 and an optical grouping unit 403.

  In this embodiment, the wavelengths of the input optical fibers B are initially grouped into groups B1 and B2. Here, assuming that the wavelength of the input optical fiber B needs to be grouped into n groups, the input optical fiber B is input to the optical grouping unit 403 by the optical switching unit 402, and the optical grouping unit 403 is The optical grouping unit 403 can output the n groups to an arbitrary output port by grouping the wavelengths into n groups and then transmitting the grouped wavelengths to the optical switching unit 402. , Output grouping and expansion is realized. The optical grouping unit 403 is expanded by expanding the optical grouping subunit.

The specific flow is as follows.

The switching flow is as follows.

  Furthermore, the switching dimension may be extended by the optical grouping subunit. Assume that at time T1, the input optical fiber B is required to be output in 9 dimensions, and at time T2, the input optical fiber B is required to be output in 17 dimensions.

  At time T1, referring to FIG. 4A, the difference is that the number of dimensions of the output optical fiber is 9, not n. The input optical fiber B is required to be output in 9 dimensions, and this request is realized by the grouping subunit 1. That is, the input optical fiber is input to the grouping subunit 1 through the optical switching unit 402. The grouping subunit 1 groups the input optical fibers into nine groups, and then outputs the grouped optical fibers to the output. For transmission to the optical switching unit 402. At time T2, as shown in FIG. 4B, the optical grouping unit 403 is formed of optical grouping subunits. The number of output dimensions of the input optical fiber B is changed to 17, which is achieved by adding one level of optical grouping subunit 2. The first level optical grouping subunit 1 is regrouped, that is, the output of one group is transmitted to the optical switching unit 402 and input to the second level optical grouping subunit 2, and the optical grouping subunit 2 groups the wavelengths. Then, the grouped wavelengths are transmitted to the optical switching unit 402 in order to realize a 17-dimensional output.

  In this embodiment, the optical switching process is completed by grouping optical signals using an optical grouping unit and then switching the optical signals using an optical switching unit. Since the optical signals are combined on demand, the demand on the switch matrix is reduced and the ports of the optical switching unit are saved.

<Embodiment 4>
One embodiment of the present invention further provides an optical switching device. This embodiment of the invention is described in the context of wavelength dispatching.

  As shown in FIG. 5, this apparatus includes an optical switching unit 502, an optical grouping unit 503, and a service switching unit 501. Assume that wavelengths λ1, λ2, λ3, and λ4 in input optical fiber B are required to be switched to optical fiber A.

  The dispatching process may be as follows. The input optical fiber B is switched to the optical grouping unit 503 via the optical switching unit 502, and the optical grouping unit 503 changes the wavelength in the optical fiber B into two groups, namely B1 (λ1, λ2, λ3, and λ4) and B2 (λ5,..., Λ80), and the grouped wavelengths are transmitted to the optical switching unit 502, and the optical switching unit 502 groups them, and B1 (λ1, λ2, λ3, and λ4) is Switching to the output port O1 together with the wavelength of the input optical fiber A, that is, the wavelengths (λ1, λ2, λ3, and λ4) are switched to the optical fiber A. The other group B2 (λ5,..., Λ80) is output via another port upon request.

  In this embodiment, the optical switching process is completed by grouping optical signals using an optical grouping unit and switching optical signals using the optical switching unit. Since the optical signals are combined on demand, the demand on the switch matrix is reduced and the ports of the optical switching unit are saved.

  It should be understood by those skilled in the art that all or part of the steps of the method according to the embodiments of the present invention may be implemented by a program including instructions to the associated hardware. The program may be stored in a computer-readable storage medium. The storage medium may be a read only memory (ROM), a magnetic disk, or a compact disk.

  The optical switching method and apparatus provided in the embodiments of the present invention have been described in detail above. The principles and practice of the present invention have been described herein by way of specific examples. The descriptions of the embodiments of the present invention are provided only to facilitate an understanding of the methods and core concepts of the present invention. Those skilled in the art can make variations and modifications to the present invention with respect to specific implementations and applications in accordance with the concepts of the present invention. Accordingly, the specification should not be construed as limiting the invention.

The present invention relates to the field of communication technology, and in particular, to an optical switching method and apparatus.

As a first aspect, an optical switching device according to an embodiment of the present invention is provided. The optical switching device includes an optical switching unit and an optical grouping unit.
A part of the output port of the optical switching unit is connected to the input port of the optical grouping unit, and the output port of the optical grouping unit is connected to the input port of the optical switching unit.
The optical switching unit is configured to control a transmission path of optical signals, and the optical grouping unit is configured to group the optical signals. As a second aspect, an optical switching method according to an embodiment of the present invention includes:
Receive the input optical signal,
When the input optical signal needs to be grouped, switch the optical signal to the optical grouping unit, receive the grouped optical signal,
Switching the grouped optical signals to corresponding output ports for output;
Realized by technical solutions including:

Claims (12)

Receive the input optical signal,
When the input optical signals need to be grouped, switch the input optical signals to an optical grouping unit, and then receive the grouped optical signals;
Switching the grouped optical signals to a corresponding output port for output. The method comprises: after receiving the input optical signal,
If the input optical signal requires service switching, switch the input optical signal to a service switching unit, and then receive the service-switched optical signal;
The method of claim 1, further comprising: switching the service-switched optical signal to a corresponding output port for output. Switching the grouped optical signals to the corresponding output port for output,
Transmitting a part of the grouped optical signals to the optical grouping unit;
Receive the regrouped optical signal,
Outputting another portion of the grouped optical signal on a required output port and outputting the regrouped optical signal on a required output port. The method described. Output on the corresponding output port is
Outputting at least one of the optical signal on the output port after performing at least one of wavelength switching, optical fiber switching, and sub-wavelength switching on the optical signal as required. The method according to claim 1 or 2. Receiving an optical signal switched by an optical switching device;
Grouping the optical signals;
An optical switching method, comprising: transmitting grouped optical signals to the optical switching device.   The method of claim 5, wherein the received optical signal switched by the optical switching device comprises the grouped optical signal.   The method according to claim 5 or 6, wherein the grouping includes grouping according to wavelength. When the dimensions of the optical signals that need to be grouped, switched by the optical switching device, are reduced, the idle input and output ports are released.
The method according to claim 5 or 6. An optical switching unit;
An optical grouping unit;
With
A part of the output port of the optical switching unit is connected to the input port of the optical grouping unit, the output port of the optical grouping unit is connected to the input port of the optical switching unit,
The optical switching unit is configured to control a transmission path of optical signals, and the optical grouping unit is configured to group the optical signals;
Optical switching device. A service switching unit;
A part of the output port of the optical switching unit is connected to the service switching unit, an output port of the service switching unit is connected to the input port of the optical switching unit, and the service switching unit is configured to switch a service. Composed of,
The apparatus according to claim 9. The light grouping unit is formed of at least one light grouping subunit;
An input port of the optical grouping subunit is connected to the output port of the optical switching unit, an output port of the optical grouping subunit is connected to the input port of the optical switching unit, and the optical grouping subunit is the optical port. Configured to group signals,
The apparatus according to claim 9 or 10. The optical grouping subunit is further configured to release idle input and output ports when the dimensions of the optical signals that need to be grouped switched by the optical switching unit are reduced.
The apparatus of claim 11.

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